Description of the Pest
Adult fruittree leafroller moths are about 0.5 inch long, with rusty brown wings marked with areas of white and gold. When at rest the adults show the typical bell-shaped pattern common to the family Tortricidae. The eggs are laid in masses on limbs and twigs and are covered with a gray secretion that turns white upon aging. Larvae are green with a black head. The intensity of the green color varies from a light green in young larvae to a darker green as they mature. Fruittree leafroller larvae are difficult to distinguish from the more damaging obliquebanded leafroller larvae.
The fruittree leafroller overwinters in the egg stage. Eggs usually hatch in early spring. Larvae feed within opening buds. As they mature they tie leaves together and feed on leaves, blossoms, and small fruit. Adults emerge in May or June. These adults then lay egg masses that overwinter. There is one generation per year.
Damage
Larvae feed on leaves and buds, webbing them together to form a protective case. Fruit damage is usually shallow and superficial and often occurs when leaves and fruit are webbed together.
Management
Delayed dormant treatments and bloom or petal fall applications for other pests help keep leafroller numbers under control. However, regular monitoring each season is important so that prompt action can be taken if damaging levels develop. Monitor throughout the season for leafrollers and other pests.
Biological Control
A number of parasites, including species of Macrocentrus, Cotesia (=Apanteles), and Exochus, attack leafroller larvae. General predators such as lacewings, assassin bugs, and minute pirate bugs may feed on eggs and larvae. Preservation of natural enemy populations is an important part of keeping leafroller numbers low. Use selective materials that are least disruptive of biological control when treating other pests.
Organically Acceptable Methods
Use sprays of Bacillus thuringiensis and the Entrust formulation of spinosad on organically grown apricots.
Monitoring and Treatment Decisions
Examine tree prunings during the dormant season for egg masses. In early spring (March–April), check the orchard for larvae and feeding damage. When necessary, apply an insecticide at petal fall or shortly thereafter. Pheromone traps are available but are not useful for monitoring since adult emergence occurs after the larval damage is completed.
| Common name | Amount to use** | REI‡ | PHI‡ | ||
|---|---|---|---|---|---|
| (Example trade name) | (conc.) | (dilute) | (hours) | (days) | |
| Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used. | |||||
| A. | SPINOSAD | ||||
| (Entrust)# | 1.25–2.5 oz | 0.42–0.83 oz | 4 | 14 | |
| (Success) | 4–8 fl oz | 1.3–2.7 fl oz | 4 | 14 | |
| MODE-OF-ACTION GROUP NUMBER1: 5 | |||||
| COMMENTS: Most effective when applied at petal fall. This product is toxic to bees for 3 hours following spraying; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. Apply in the late evening after bees have stopped foraging. Do not apply more than 29 fl oz/acre per year of Success or 9 oz/acre per year of Entrust. | |||||
| B. | SPINETORAM | ||||
| (Delegate WG) | 4.5–7 oz | 1.125–1.75 oz | 4 | 14 | |
| MODE-OF-ACTION GROUP NUMBER1: 5 | |||||
| COMMENTS: This product is toxic to bees for 3 hours following treatment; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. Apply in the late evening after bees have stopped foraging. Do not apply more than 28 oz/acre per year or make more than four applications per year. | |||||
| C. | CHLORANTRANILIPROLE | ||||
| (Altacor) | 3–4.5 oz | 0.75–1.125 oz | 4 | 10 | |
| MODE-OF-ACTION GROUP NUMBER1: 28 | |||||
| COMMENTS: Do not apply more than 9 oz/acre per year or make more than three applications a year. Do not apply with less than 100 or more than 200 gallons water/acre. | |||||
| D. | BACILLUS THURINGIENSIS ssp. KURSTAKI# | ||||
| (various products) | Label rates | — | 4 | 0 | |
| MODE-OF-ACTION GROUP NUMBER1: 11A | |||||
| COMMENTS: Make two applications during bloom: the first between popcorn and the beginning of bloom and the second 7 to 10 days later, but no later than petal fall. Good coverage is essential. Ground application using a concentrate rate (80–100 gal water maximum) is preferred. If aerial applications must be made because conditions do not permit ground application, a concentrate rate (5 gal or less) is preferred. Fly material on at a height of about 20 feet over the canopy using appropriate nozzles to allow better deposition on the tree tops. Compatible with fungicide sprays, and can be tank mixed with them. For tank mixes, observe all directions for use on all labels, and employ the most restrictive limits and precautions. Never exceed the maximum a.i. on any label when tank mixing products that contain the same a.i. | |||||
| E. | METHOXYFENOZIDE | ||||
| (Intrepid 2F) | 8–16 fl oz | 2–4 fl oz | 4 | 14 | |
| MODE-OF-ACTION GROUP NUMBER1: 18 | |||||
| COMMENTS: Do not apply more than 16 fl oz/acre per application or more than 64 fl oz/acre per season. | |||||
| F. | PHOSMET | ||||
| (Imidan 70-W) | 2.125–4.25 | 1 lb | 7 days | 14 | |
| MODE-OF-ACTION GROUP NUMBER1: 1B | |||||
| G. | DIAZINON* | ||||
| (Diazinon 50W) | 1 lb/100 gal | 4 days | 21 | ||
| MODE-OF-ACTION GROUP NUMBER1: 1B | |||||
| COMMENTS: Avoid drift and tailwater runoff into surface waters. Where apricots are grown adjacent to waterways, do not use this material. Do not apply more than 4 lbs product per application. | |||||
| ** | For concentrate applications, use the amount given in 80 to 100 gal water/acre or lower if the label allows; for dilute application, amount is per 100 gal water to be applied in 300 to 400 gal water/acre, according to label. |
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest. |
| # | Acceptable for use on organically grown produce. |
| 1 | Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-actiong group number more than twice per season to help prevent development of resistance. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee). |
| — | Not recommended or not on label. |
| * | Permit required from county agricultural commissioner for purchase or use. |